Carrier Indicator Field for Multi-Carrier CQI Reporting
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Solution Overview
Problem
Current wireless communication systems, particularly 3GPP LTE, face challenges in reporting channel quality in multi-carrier systems, where the introduction of multiple carriers complicates the reporting of channel quality indicators (CQI) due to ambiguity in carrier allocation and linkage between uplink and downlink component carriers.
Innovation Solution
A method and apparatus for reporting channel quality in a wireless communication system that involves receiving an uplink grant from a base station through one of multiple downlink component carriers, which includes a channel quality indicator (CQI) triggering and a carrier indicator field (CIF) to determine the linked downlink component carrier for CQI reporting, allowing for cross-carrier scheduling and dynamic linkage between uplink and downlink carriers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple carriers are introduced to increase bandwidth and improve system capacity, then productivity and data transmission capability are improved, but device complexity and difficulty of detecting and measuring channel quality increase
Solution Approach 1:
The system segments the multi-carrier channel quality reporting into separate CQI reports for each downlink component carrier. Each CQI report contains a carrier indicator field (CIF) that identifies which downlink CC the CQI corresponds to, allowing the UE to report channel quality for multiple carriers independently and clearly, thus managing the complexity of multi-carrier systems through structured segmentation.
Solution Approach 2:
The patent introduces a new dimension (carrier indicator field/CIF) to the existing CQI reporting structure. This additional dimension allows the system to distinguish between multiple downlink component carriers in the reporting mechanism, transforming the single-carrier reporting model into a multi-carrier capable model without fundamentally changing the CQI measurement process.
2Adaptability or versatility
If cross-carrier scheduling is implemented to flexibly allocate uplink and downlink carriers, then adaptability is improved, but difficulty of detecting and measuring channel quality increases
Solution Approach 1:
The carrier indicator field (CIF) acts as an intermediary element that links the uplink grant received on one downlink CC with the corresponding downlink CC for which CQI should be reported. This intermediary clearly identifies the target downlink carrier, eliminating ambiguity in cross-carrier scheduling scenarios where the uplink and downlink carriers may be different.
Solution Approach 2:
The system performs preliminary configuration of carrier linkages through higher layer signaling (RRC messages) before actual data transmission. This preliminary action establishes the mapping relationships between uplink and downlink component carriers in advance, so that when cross-carrier scheduling occurs, the UE already knows which downlink CC corresponds to which uplink CC for CQI reporting purposes.
3Use of energy by moving object
If carrier aggregation is used to utilize fragmented frequency bands, then use of energy and spectrum efficiency are improved, but device complexity increases
Solution Approach 1:
The CQI reporting mechanism is designed with universal applicability to both single-carrier and multi-carrier scenarios. The same basic CQI reporting structure is used, but with an optional carrier indicator field that becomes active in multi-carrier mode. This multi-functionality allows the system to utilize fragmented frequency bands through carrier aggregation while using a unified reporting framework that handles both aggregation and non-aggregation cases.
Data Source
AI summary
The present invention provided a method and apparatus for reporting a channel quality in a wireless communication system. A terminal receives an uplink grant from a base station via one of a plurality of downlink component carriers (CCs). The uplink grant includes a channel quality indicator (CQI) request for instructing uplink allocation and CQI reporting. The terminal reports the CQI of the downlink CC being linked to the base station. The downlink CC being linked is one of the plurality of downlink CCs, which is linked to the uplink CC for which the uplink allocation is scheduled.A method and an apparatus for reporting channel quality are discussed. The method according to an embodiment includes receiving, by a terminal configured with a plurality of downlink component carriers (CCs), control information from a base station, the control information including an uplink allocation and a CQI request, the control information including a carrier indicator field (CIF) indicating an uplink CC in which the uplink allocation is scheduled; and transmitting, by the terminal to the base station, the CQI through an uplink CC. The CQI request indicates one of: a triggering of CQI reporting for one downlink CC linked to the uplink CC, indicated by the CIF, among the plurality of downlink CCs; and a triggering of CQI reporting for a first group of downlink CCs among the plurality of downlink CCs.